Diane Warren’s Guitar Teacher Said ‘She Has No Future in Music’ (Exclusive)

A 15-time Academy Award nominee with songs that have sold more than 125 million records, Diane Warren embarked on a journey to success that began as a dream that few thought would become a reality.

In the upcoming intimate documentary Diane Warren: Ruthlesspremiering in theaters on January 10 and available for streaming on MasterClass on January 16, the 68-year-old songwriter offers a behind-the-scenes look at her upbringing and creative process.

“My mom always said, ‘You could sit on the corner with a guitar and a cup,’” Warren says in the film’s trailer, shared exclusively with PEOPLE. “You can’t make a living from it.”

Despite discouragement from her mother and others in her life – including her childhood guitar teacher, who told her father, “She has no future in music” – Warren persevered, honed her craft and eventually became a favorite songwriter for the stars. “One of my favorite things to do is say, ‘F— you, I’m going to prove you wrong,'” she says in the trailer.

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Warren has written some of the biggest songs for the world’s biggest artists – including “I Don’t Wanna Miss a Thing” for Aerosmith, “If I Could Turn Back Time” for Cher and “Because You Loved Me” for Céline Dion. But she says there is no secret formula to her songwriting: “I don’t analyze what I do. I just go to work and I work.”

Several of the many artists she has collaborated with appear in the documentary and reflect on Warren’s impact. “I’ve met a lot of people, but honey, I’ve never met anyone like Diane Warren,” Jennifer Hudson says in the trailer. “She’s crazy, oh my god,” Cher adds with a laugh. “But she writes great songs.”

The documentary also explores Warren’s early diagnosis of Asperger’s syndrome, which played a role in her creative process. “Many people don’t fully understand people on the spectrum. It’s part of the genius,” says a voiceover in the trailer, while another adds: “She relived her pain and shared it with the world.”

Despite the challenges she faced growing up (“As a child, she knew nothing but rejection,” a voiceover says), Warren is grateful for the life she has led. “I don’t want to change anything because it got me here,” she says.

And what it earned her was an Honorary Academy Award, a Grammy Award, an Emmy Award, two Golden Globe Awards and three consecutive Billboard Music Awards for Songwriter of the Year, from 1997 to 1999. ‘All these hits. One writer, one genius, named Dianne Warren,” Randy Jackson says in the trailer. Common adds: “She is one of the greatest songwriters of all time – and remains so.”

And as she says in the trailer, Warren has no plans to slow down: “It’s about your job. I’m still hungry. This isn’t a job, this is my life. You cannot withdraw from your life.”

Diane Warren: Ruthless premieres in theaters on January 10 and will be available for streaming on MasterClass on January 16.